This invention relates to disposable plates, trays, containers, bowls, and related articles of commerce useful for the preparation, storage, delivery, and serving of food, wherein convenience and low cost are of paramount importance. Nevertheless, appearance and tactile characteristics of the plate, container, etc., are important for consumer preference. The suitability of these disposable articles of manufacture to microwave cooking, or heating of food, has an important place in today's marketplace. Both the commercial and retail market components need an aesthetically pleasing microwaveable, disposable, rigid and strong container, plate, tray, bowl and related article of manufacture. This invention is directed to economically meeting that need and provides a container, plate, tray or bowl comprising an extruded sheet of polypropylene or propylene-ethylene copolymer or blend coupled with mica and talc.
These disposable microwaveable containers including plates, bowls, cups, trays, buckets, souffle dishes, and lids exhibit (a) a micronodular surface on at least the food contact side of such container, and (b) a melting point of no less than about 250.degree. F., said container or plate being dimensionally stable and resistant to grease, sugar, and water at temperatures up to at least 220.degree. F. and exhibiting sufficient toughness to be resistant to cutting by serrated polystyrene flatware. Microwaveable and disposable containers and plates comprising talc and mica are not known in the prior art. In U.S. Ser. No. 08/733,463 filed on Oct. 18, 1996, and assigned to the assignee of the present patent application, now abandoned, mica filled polypropylene food contact compatible microwaveable containers are disclosed. In U.S. Pat. No. 5,377,860, assigned to assignee of the present patent application, a double shell food container is disclosed. The composition and properties of the container differ from the present invention since a polypropylene/talc/mica composition is not suggested or disclosed and the container does not have the thermal properties or the micronodular surface of the containers disclosed herein. The filled polypropylene compositions comprise about 10 to 40% by weight talc, 10 to 40% mica, wherein the total filler composition does not exceed about 40 to 50% by weight of the total polypropylene filler composition. The containers disclosed in European Patent Application D544,429A1 do not suggest or disclose a container which can meet the thermal properties and have the desirable micronodular surface of the container of the present invention.